Spraying foam? Enter the area and thickness. You get the board feet, the kits to buy and the R-value you reach.
Your shopping list
2Kits to buy
1,150 board feetBoard feet with extra
13 RR-value you reach
- Board feet before extraArea x thickness1,000 board feet
One board foot is one sq ft sprayed one inch thick. Extra of 15% is included.
How to use the Spray Foam Insulation Calculator
- Measure the area to be sprayed.
- Pick closed-cell or open-cell foam and the thickness in inches.
- Pick the size of kit and read how many to buy.
The math behind it
Board feet = area x thickness in inches
Board feet with extra = board feet x (1 + extra %)
Kits = board feet with extra / kit yield, rounded up
A worked example
What we typed in
- Area to spray: 800 sq ft
- Foam thickness: 3 in
- Foam type: Closed-cell foam (about R-6.5 per in)
- Size of one kit: 600 board feet kit
- Extra for mistakes and cuts: 15%
What we got
- Kits to buy: 5
- Board feet with extra: 2,760 board feet
- R-value you reach: 19.5 R
- Board feet before extra: 2,400 board feet
Tips from the job site
- Kit yield on the box is the best case. Plan for less on a cold day.
- Spray in layers under 2 in thick so the foam cures well.
Common questions
What is a board foot of spray foam?
One square foot sprayed one inch thick.
Closed-cell or open-cell?
Closed-cell gives more R-value per inch and stops moisture. Open-cell costs less and fills a thick cavity.
See all Insulation Calculators.
Last checked: (worked example and form display).